A number of structurally unique C11N5 marine metabolites containing guanidine and either brominated or nonbrominated pyrrole moieties have been isolated from various sponges.1 Among these are the tricyclic natural products hymenin (1),2 stevensine (2),3,4 hymenialdisine (3),4-8 and debromohymenialdisine (4).4-9 This group of natural products share in common a fused bicyclic pyrrolo[2,3-c]azepin-8-one ring system that bears either a 2-aminoimidazole (AI) or glycocyamidine appendage. Their structures were elucidated primarily from spectral studies in comparison with biogenetically and structurally related sponge metabolites. The X-ray crystal structure of 3 has been reported by two research groups.5,6 Hymenialdisine (3) is the only metabolite among the C11N5 and dimerically related natural products that contains a monobromo pyrrole moiety in which the bromine atom is situated in the a position.10 This invention describes a synthesis of this family of natural products consisting of 1-4.
The present invention provides a process for producing hymenialdisine and debromohymenialdisine from hymenin via several different pathways for their synthesis.
The present invention further provides the novel compounds which are more fully described and depicted in the Detailed Description, Experimental Details, Claims and Figures. These novel compounds are intermediates or by products of the above pathways. As these compounds are produced in the synthesis of hymenialdisine and debromohymenialdisine, the process for producing these novel compounds is also provided by this invention.